SpeedFan uses command line parameters to achieve tasks that can't be automatically done by SpeedFan
autodetection routines. A command line parameter (also named "command line switch") can be added to
any command line used to run any software. The software will then parse available switches and use
them according to its specifications. In the image to the right you can see how command lines
parameters can be added to shortcut's properties. When you open shortcut's properties to enter a
switch, you will find the target field already filled with the proper string to launch
SpeedFan. Please note that if the path to the executable includes any space, the whole string (up to
the executable name) needs to be enclosed in double quotes. Double quotes can be used even if there
is no space in the path. Switches (more than one switch can be specified) need to be separated by
spaces. In the image you can see how the /nosuperio command line parameter should be added
to the target field that already contained "E:\Program Files\sf\speedfan.exe". SpeedFan makes
no difference between upper and lower case when looking at command line switches. You can use any
mix of upper and lower case as you like. If you need to enter more than one command line parameter,
you should enter a line like this:

"E:\Program Files\sf\speedfan.exe" /nosuperio /nosmartscan

The /NOPCISCAN switch

This switch will prevent SpeedFan from accessing the PCI BUS. This means that it won't detect video
cards, south bridges and the likes. This switch will basically prevent most operations. Almost no
SMBus will be found. It can be used as an extreme test to find what is causing SpeedFan to hang. If
your sensors are located on the ISA BUS you might still get all relevant info about your system
even if you use this switch.

The /NOSMBSCAN switch

Most sensors are accessible through the SMBus. If you use this switch, the SMBus will be detected,
but not accessed or scanned for devices. If SpeedFan hangs while scanning the SMBus then there
might be some dumb or custom device that doesn't like SpeedFan probing routines. SpeedFan probes
for devices in a way that should minimize side effects and, actually, this process works fine
on 99.99% of known motherboards. You can use this switch to speed things up too. If you already
launched SpeedFan and found that no relevant info need to access the SMBus, then you can use
this switch to prevent SpeedFan from scanning it.

The /NOSUPERIO switch

The SuperIO chip contains several functionalities. From the keyboard interface, to floppy,
serial and parallel ports, power management and so on. Some SuperIO chips also contain hardware
monitoring capabilities and/or fan control support. This is the reason why SpeedFan tries to
automatically identify them. This works most of the time, but it looks like that some manufacturers
are using custom devices and configurations that collide with this detection process. Such
manufacturers include DELL (but not all DELL products). If SpeedFan hangs or causes your system to
crash, this switch will be a good candidate for a fix.

The /SLOWDETECT switch

This switch was added a long time ago and I never suggested anybody to use it. It might lead to
interesting results though. Basically it allows SpeedFan to check the SMBus in a slower way.
Usually SpeedFan does a preliminary test at every SMBus address. If no device answers that test
SpeedFan completely ignores that address. If you use this switch, SpeedFan will query all SMBus
addresses for data. The process will certainly take longer and it might cause the system to hang.
It has not been extensively tested, but, on some systems it might even fix a crash. Anyway: I
suggest only advanced and experienced users to use it.

The /TIGERMP switch

This is the only switch that was ever added to support any specific motherboard. It is needed
to enable full TYAN TigerMP support. The BIOS for this motherboard won't initialize hardware
monitoring unless you enter the relevant page in BIOS setup. You need to do this whenever you
reboot your system. This is not, obviously, a viable everyday option. Since the BIOS doesn't
even set an I/O space for one device, SpeedFan can't do that automagically (it actually might,
but it might cause troubles) and this switch needs to be used.

The /NOTIMER switch

If you use this switch, SpeedFan will do everything but starting the timer. The timer is what
makes SpeedFan update readings. If you just want to see what SpeedFan detects on your system,
this is the right option for you. If SpeedFan properly starts on your system, but it hangs
after a few seconds, this switch will let you use the SEND REPORT facility on the INFO tab
to contact me and try to find a fix for your issue. There is no danger in using this switch.

The /NOSMARTSCAN switch

SpeedFan uses standard calls to the OS to access S.M.A.R.T.
info. Unfortunately, some drivers do not work fine and cause the whole system to crash when
queried the standard way. Such drivers included some from Silicon Image and some others from
nVidia (for nForce 4). You will see that every S.M.A.R.T. enabled tool will crash with such
drivers. This switch will prevent SpeedFan from accessing S.M.A.R.T.. You will not see any
info about your IDE or SATA hard disks.

The /NOSCSISCAN switch

According to my knowledge, SpeedFan SCSI access never caused any issue. This switch will
prevent SpeedFan from accessing SCSI devices at all.

The /NOACPISCAN switch

ACPI is for Advanced Configuration and Power Interface. On some computers, SpeedFan can
read no other temperature, but the one(s) exposed through this method. Usually this is
a redundant reading and you can safely use this switch to completely prevent SpeedFan from
looking for it. A better option would be to enter CONFIG and to hide the relevant reading
in the temperature tab.

The /NOTOSHIBA switch

This switch prevents SpeedFan from checking for a specific device driver from Toshiba
that enables turning the fan on and off. There is no real reason to use this switch and
I never suggested anybody to use it to fix any issue.

The /NOASUSSCAN switch

SpeedFan checks for ASUS SMARTDOCTOR and it can access its readings on some systems.
This has been obsoleted by latest video card access routines. If you don't want SpeedFan
to access your SmartDoctor, feel free to use this command line parameter.

The /NONVIDIAI2C switch

NVidia Video Cards might include some sensors available on the I2C BUS. I2C is a superset
of the SMBus. Since NVidia chose not to support SpeedFan, I had to add support for it to
the best of my knowledge and findings. If SpeedFan hangs or slows down accessing the I2C
bus from NVidia, you can use this switch to prevent SpeedFan from accessing it at all.
You will no longer see any reading that was using this bus. On Intel systems with
HyperThreading enabled you will see a 50% usage even at system idle when SpeedFan collides
with something else accessing the video card and is no longer able to gather info from it.
If this is what happens to you, feel free to use this switch to fix the issue.

The /NOAMDK8SCAN switch

Internal core temperature access for AMD K8 class CPUs can be disabled usig this switch.
It is unlikely that you will ever need to use it.

The /SMBDEBUG switch

This switch can be used to do SMBus advanced debugging. You can find the full explaination
for it in the online help file (just press F1 while running SpeedFan).